Method of fabricating hollow frame structures for boats and the like

ABSTRACT

The method of fabricating hollow frame structures for boats and the like of fiberglass reinforced plastic consists of the steps of the simultaneous production of an inner and outer matching shells on a male and female mold respectively by the conventional laying up of glass fibers and resins. Upon partial curing of the outer and inner shells, an adhesive is applied to the exposed contacting surfaces. The inner shell is removed from the male mold and superimposed on the matching outer shell. The configuration of the inner shell provides a plurality of longitudinal and/or transverse stiffeners forming a plurality of communicating chambers between the two shells and an opening is then made in the inner shell for connecting a vacuum creating apparatus thereto. The edges of the superimposed shells having been trimmed prior to removal from their mold as rendered airtight upon placing a tape along the juncture thereof. Upon applying a partial vacuum to the communicating chambers, atmospheric pressure will exert an even pressure against all faying or contacting surfaces to effect a proper adhesion of the inner and outer shell sections to form a hollow frame structure of fiberglass reinforced plastic.

United States Patent 1191 Winters Nov. 27, 1973 [75] Inventor: HenryWinters, North Miami, Fla.

[73] Assignee: Salvatore G. Militana, Miami Shores, Fla. a part interest22 Filed: July 19, 1971 211 Appl.No.: 163,656

52 use: ..l56/245,9/6,156/285, 156/286, 156/287, 156/288, 264/250,264/102 51 Int. Cl. ..B29c 5/00,B29g 5/00 [58] Field ofSearch 9/6, 6.5,242;

Primary Examiner-Alfred L. Leavitt Assistant ExaminerFrank FrisendaAttorney-Salvatore G. Militana [57] ABSTRACT The method of fabricatinghollow frame structures for boats and the like of fiberglass reinforcedplastic consists of the steps of the simultaneous production of an innerand outer matching shells on a male and female mold respectively by theconventional laying up of glass fibers and resins. Upon partial curingof the outer and inner shells, an adhesive is applied to the exposedcontacting surfaces. The inner shell is removed from the male mold andsuperimposed on the matching outer shell. The configuration of the innershell provides a plurality of longitudinal and/or transverse stiffenersforming a plurality of communicating chambers between the two shells andan opening is then made in the inner shell for connecting a vacuumcreating apparatus thereto. The edges of the superimposed shells havingbeen trimmed prior to removal from their mold as rendered airtight uponplacing a tape along the juncture thereof. Upon applying a partialvacuum to the communicating chambers, atmospheric pressure will exert aneven pressure against all faying or contacting surfaces to effect aproper adhesion of theinner and outer shell sections to form a hollowframe structure of fiberglass reinforced plastic.

4 Claims, 13 Drawing Figures PAIENTEUNOv27 1913 saw 1 or 8PATENTEU-HUY27 I915 SHEEI 2 OF 8 l.\"\ TOR PATENTED NOV 2 7 I975 SHEET 3BF 8 By 2% Mm PAIENIEnuuvzv ms 3775214 sum 5 or 8 PATENTED NOV 2 7 I975SHEET 6 OF 8 FIGB I N VEN TOR.

PATENIEMnvm I913 3.775.214 sum 7 or 8 aw/9 m BACKGROUND OF THE INVENTIONThis invention relates to the fabrication of hollow frame structuressuch as boats and the like wherein the hull is formed in two matchingshells simultaneously which are superimposed one on the other with anadhesive having been sprayed on the contacting surfaces and a vacuumapplied to the chambers formed by the non-contacting surfaces. At thepresent time the conventional manner of fabricating a hull is by layingup fiberglass reinforced plastic on a female mold and permitting theplastic to cure after which wood framework or previously preparedindividual hollow fiberglass frames are fastened and bonded into placein the hull. Then when the proper curing of the plastic has takeneffect, the hull is removed from the female mold and the female mold isprepared for fabricating a further hull. It is readily noted that thetime during which the female mold is in use to produce one hull is longtaking as much as 1 week, and therefore costly as well as having torequire the use of highly skilled labor in the placement of theframework in the hull. Also, the work- 7 ers are exposed to toxic fumesduring this time. It has PURPOSE OF THE INVENTION It is the main purposeof the present invention to provide a method of fabricating ahollowstructure such as boat hulls and the like which method lends itselfreadily to the mass production of the structures thereby reducing thecosts of production as well as reducing to a minimum the time in which amold is in use to produce one such structure.

Another object of the present invention is to provide a method offabricating a fiberglass structure such as a boat and the like, whichrequires the use of semi or unskilled labor and which does not requirethe workers to expose themselves to toxic fumes or otherwise dangerousconditions.

A further object of the present invention is to provide a method offabricating a reinforced plastic boat which results in a hollow framestructure that is as strong as the solid or hollow frame structuresproduced by the conventional method without the use of fasteners and thelike, and whose exposed surfaces become finished in the normal course offabrication.

A still further object of the present invention is to fabricate a boathull and the like by a method which not only lends itself to massproduction methods but also permits quality control of a constant andhigh degree.

In the drawings:

FIG. 1 is a perspective view of a hull of a boat manufactured inaccordance with my method of fabrication.

FIG. 2 is a top plan view thereof.

FIG. 3 is a transverse cross sectional view of a conventional mold inwhich the outer hull shell is shown being molded.

FIGS. 4 and S are cross sectional views taken along the lines 4-4 and5-5 respectively of FIG. 6 shown in position in a conventional mold forforming the inner hull shell.

FIG. 6 is a longitudinal cross sectional view of the inner hull shell.

FIGS. 7 and 8 are similar to FIG. 3 with the inner hull shell inposition, the sections being taken along the same lines as shown byFIGS. 4 and 5, respectively.

FIG. 9 is a cross sectional view of the completed hull as shown removedfrom the mold.

FIGS. 10 and 11 are cross sectional views of an outer and inner deckshells respectively.

FIG. 12 is a cross sectional view of the completed deck.

FIG. 13 is a cross sectional view of a completed boat.

Referring to the drawings wherein like numerals are used to designatesimilar parts throughout the several views, the numeral 10 refers to thehull of a boat constructed in accordance with my method of fabricationand consisting of an outer or exposed hull shell E and an inner hullshell I.

The outer and inner hull shells E and I are each fabricatedsimultaneously and separately in the conventional manner of laying up onan appropriate mold, the glass fibers and resins such as polyesters orepoxy and letting them set at least to a partial curing.

As shown by FIG. 3, the outer hull shell E is fon'ned within aconventional one-piece female mold 11 which is supported by the supportstructure 12. The shape of the mold which is such as to produce thedesired shaped boat hull is first polished with wax or a mold releaseliquid or parting agent such as polyvynil alcohol is then applied to theentire inside surface of the female mold l l. A gelcoat is then sprayedon the mold 11, the gelcoat consisting of a polyester resin with pigmentand filler. Alternate layers of fiberglass mat and woven rovingsaturated with polyester resin are placed in the mold 11 conforming toand following the configuration of the mold 11 so that the outer hullshell E will have the same configurations as the mold 11. At roomtemperature, the resins will cure in about 6 hours, or if desired heatmay be applied to cause the curing effect to take place in a lesserperiod.

Simultaneously with the laying up of the outer hull shell E, the innershell I is laid up on a conventional male mold 13 supported on a support14. The same proceedure given above in the laying up of the outer hullsection 10 is followed in the formation and partial curing of thematching inner hull section I. However, the configuration of the mold 13is such that the inner hull shell I will be formed with a plurality oflongitudinal stiffeners l5 and a plurality of transverse stiffeners 16extending along the full length of the hull I and interconnecting withthe longitudinal stiffeners 15. A hole 17 is now bored in the innershell I at the position of one of the longitudinal stiffeners 15 at thejuncture of a transverse stiffener 16 into which opening 17 a pipefitting 18 is mounted.

To the entire exposed surfaces of the inner and outer hull shells I andE while preferably lying in their respective molds 13 and 11, there isapplied an adhesive of polyester or expoxy resin with glass fiberfiller. While the outer shell E continues to remain on the mold l1,

the inner shell I is removed from its mold l3 and superimposed on theouter shell E, as shown by FIG. 7. The edges 19 of both of the hulls arenow trimmed and the juncture of both edges 19 sealed by a tape 20 toprevent any leakage of air therebetween. The longitudinal and transversestiffeners 15 and 16 respectively which are now rigid, formcommunicating chambers or recesses 21 and 22 that extend to the edges 19of the hulls l and E.

To the fitting 18, there is connected a vacuum creating apparatus Vconsisting of a pipe 25 on which a valve 26 is mounted, the pipe 25extending to a tank 27. The tank 27 is connected by a pipe 28 thatextends to the intake of a vacuum pump 29 whose outlet 30 is open to theatmosphere. While the adhesive of polyester or epoxy is still moist, thevacuum pump 29 is actuated to pump air out of the tank 27, dischargingthe air into the atmosphere and thereby creating a partial vacuum orpressure differential of from 2-3 psi in the tank 27 and the recesses orchambers 21 and 22. When the desired vacuum pressure has been attainedin the tank 27, the valve 26 is opened to subject the shells I and E tothe pressure difierential. This differential pressure is insufficient tocause a collapsing of the hollow structures of the longitudinal andtransverse stiffeners 15 and 16 but does cause a firm and even mating ofthe contacting surfaces of the hulls E and I. This curing period extendsover a few hours, making it possible to fabricate a complete hull withinone day by molding the inner and outer hulls I and E simultaneously andpermitting the adhesive cementing the hulls together to cure overnight.The next morning, the combined hull structure 10 is removed from thefemale mold 11 and is now ready to received a deck and other componentssuch as engines, bulk-heading, interior panelling and the like.

It is to be noted that by this method, the exposed surfaces of the hull10, namely the lower surface of the outer hull E and the upper surfaceof the inner hull I are a finished and smooth surface requiring nofurther finishing. Also, if additional reinforcements are required in aboat hull, they can readily be incorporated in the inner hull shell whenbeing molded and become integrated into the hull structure when theinner and outer hull shells are cemented together by my vacuum method.

As shown by FIGS. 1-12 inclusive, the deck structure is fabricated byuse of the same method described hereinabove. The outer deck shell 40 isfabricated on a female mold (not shown) in the conventional manner atthe same time an inner matching deck shell 41 is fabricated on a malemold. The inner deck shell 41 is formed with hollow longitudinal and/ortransverse stiffeners 42 and 43 that form communicating chambers whenthe outer deck shell 40 is superimposed on the female deck shell 41 asshown by FIG. 12. An adhesive is then applied to the surfaces thatcontact each other when the outer deck shell 40 is superimposed on theinner deck shell 41 and the inner and outer peripheral edges 44 and 45of the shells 40 and 41 are trimmed. Then tape 46 is applied thereover.A hole 48 having previously been bored in the inner deck shell thatcommunicates with the chambers formed by the hollow stringers 42 and 43is provided with a vacuum fitting 49 to which the previously describedvacuum creating apparatus V is connected. A vacuum pressure of 2-3 lbs.per square inch is maintained until the adhesive cementing the deckshells 40 and 41 together has become set. Then the combined deck shells40, 41 are placed in position on the combined hull structure 10 andcemented along the edges 45 of the deck shells and the edges 19 of thecombined hulls 10 in the conventional manner to complete fabrication ofthe boat.

What I claim as new and desired to secure by Letters Patent of theUnited States is:

l. The method of fabricating a hollow frame structure for boats and thelike comprising the fabricating of an outer shell of fiberglassreinforced plastic on a first mold and the fabricating of an innermating shell on a second mold, said second mold having a configurationforming hollow stifieners on said inner mating shell, said integralhollow stiffeners extending along said inner shell and being curedsufficiently to be self supporting, applying an adhesive to at least aportion of the faying surfaces of said outer and inner shells,superimposing said inner shell on said outer shell, said stiffenersforming chambers, sealing the juncture of edge portions of said shellsand applying a partial vacuum to said chambers whereby said fayingsurfaces are drawn toward each other until said adhesive becomes curedand the outer surfaces of the combined inner and outer shells becomeformed in a finished condition.

2. The method as recited by claim 1 wherein the edges of said outer andinner shells are trimmed and said inner shell is removed from saidsecond mold prior to being superimposed on said outer shell and applyingsaid adhesive only to that portion of each of said exposed surfaces thatcontact each other when said inner shell is superimposed on said outershell.

3. The method as recited by claim 2 wherein said combined inner andouter shells form the hull of a boat.

4. The method as recited by claim 3 taken in combination with a secondinner and outer shell fabricated and combined in substantially the samemethod as said first named inner and outer shells to form decking andadhesive means applied along edge portions of either of said hull ofsaid boat or of said decking and positioning said decking on said hullto form a completed boat structure.

t t i t

1. The method of fabricating a hollow frame structure for boats and thelike comprising the fabricating of an outer shell of fiberglassreinforced plastic on a first mold and the fabricating of an innermating shell on a second mold, said second mold having a configurationforming hollow stiffeners on said inner mating shell, said integralhollow stiffeners extending along said inner shell and being curedsufficiently to be self supporting, applying an adhesive to at least aportion of the faying surfaces of said outer and inner shells,superimposing said inner shell on said outer shell, said stiffenersforming chambers, sealing the juncture of edge portions of said shellsand applying a partial vacuum to said chambers whereby said fayingsurfaces are drawn toward each other until said adhesive becomes curedand the outer surfaces of the combined inner and outer shells becomeformed in a finished condition.
 2. The method as recited by claim 1wherein the edges of said outer and inner shells are trimmed and saidinner shell is removed from said second mold prior to being superimposedon said outer shell and applying said adhesive only to that portion ofeach of said exposed surfaces that contact each other when said innershell is superimposed on said outer shell.
 3. The method as recited byclaim 2 wherein said combined inner and outer shells form the hull of aboat.
 4. The method as recited by claim 3 taken in combination with asecond inner and outer shell fabricated and combined in substantiallythe same method as said first named inner and outer shells to formdecking and adhesive means applied along edge portions of either of saidhull of said boat or of said decking and positioning said decking onsaid hull to form a completed boat structure.